Aqueous OH-/H+ Dual-ion Zn-Based Batteries

Abstract

Aqueous Zn-based batteries hold multiple advantages of eco-friendliness, easy accessibility, high safety, easy fabrication, and fast kinetics, while their widespread applications have been greatly limited by the relatively narrow thermodynamically stable potential windows ( i. e. , 1.23 V) of water and the mismatched pH conditions between cathode and anode yet, which presents the challenges regarding how to maximize the output voltage and the energy density. Recently, aqueous OH - /H + dual-ion Zn-based batteries (OH - /H + -DIZBs), where Zn anode reacts with hydroxide ions (OH - ) in alkaline electrolyte while hydrogen ions (H + ) are involved in the cathode reaction in the acidic electrolyte, have been reported to be capable of broadening the working voltage and improving the energy density, which offers practical feasibility toward overcoming the above limitations. This minireview thus takes this chance to investigate the recent progress on aqueous OH - /H + -DIZBs. We will first introduce the concept and the history of such OH - /H + -DIZBs, and then pay special emphasis on the working mechanisms, the progress of the development of new batteries, and how the electrolytes improve their performance. The challenges and opportunities in this field will finally be discussed.